Honeywell T498A, T498B User Manual
T498A,B
Electric Heat Thermostats
PRODUCT DATA
FEATURES
• CSA Performance Certifled at 16A.
• CSA Certified, Underwriters Laboratories Inc. Listed
up to 5 kW at 277 Vac.
• Long life, industrial-grade Micro Switch™ mechanism.
• Rugged, engineering plastic mounting base with
captive mounting screws.
• Replaces any standard wall-mounted electric heat
thermostat.
• Classic beige styling.
• Range: 40°F to 80°F (5°C to 25°C).
GENERAL
The T498A,B Electric Heat Thermostats provide line voltage
control of electric heating equipment. A snap action switch
makes heating circuit on temperature fall.
• Locking cover and range stops are optional.
• Energy efficient and economical.
Contents
General ............................................................................... 1
Features ..............................................................................1
Specifications ......................................................................2
Ordering Information ...........................................................2
Installation ...........................................................................3
Setting and Checkout ..........................................................4
Security Features ................................................................4
Calibration ...........................................................................5
Copyright © 1996 Honeywell Inc. • • All Rights Reserved
X-XX UL
95C-10686-3
T498A,B ELECTRIC HEAT THERMOSTATS
SPECIFICATIONS
IMPORTANT
The Specifications given in this publication do not
include normal manufacturing tolerances. Therefore,
this unit may not exactly match the listed
specifications. Also, this product is tested and
calibrated under closely controlled conditions, and
some minor differences in performance can be
expected if those conditions are changed. For exact
engineering specifications, contact your Honeywell
sales representative.
Models:
T498A: Makes heating circuit on temperature fall. With
setting knob on extreme counterclockwise position,
provides single line break—spst (see Fig. 2).
T498B: Makes heating circuit on temperature fall. With
setting knob at OFF position, provides double line break
for fuse protected 240V heating circuits (see
Fig. 3). Remakes circuit no higher than -31°F (-35°C) in
OFF position. Both models available with a
thermometer located in the cover to indicate the actual
room temperature.
Setting Range:
40°F to 80°F, markings every 5°F.
Type of Switching:
Fully enclosed snap acting Micro Switch™.
T498A: Single line break (spst).
T498B: Spst with double line break (dpst in OFF position).
Wiring Connections:
Six inch (150 mm) stranded copper leadwires suitable for
connecting to aluminum wiring if approved special service
CO/ALR connectors are used. Color-coded Black to Ll
(T498A,B); Red to L2 (T498B only).
CSA Performance Certification:
16A at 208/240 Vac.
Setpoint Adjustment:
Control knob on face of thermostat.
Sensing Element:
Flat bimetallic blade.
Differential:
Approximately 3°F (2°C) nonadjustable.
Dimensions:
See Fig. 1 for nominal dimensions.
Thermometer:
Optional coil bimetal 50°F to 90°F (10°C to 30°C).
Mounting Means:
Direct mounting on NEMA standard vertical 2 x 4 inch
(50 mm x 100 mm) switch box, or 4 x 4 inch (100 mm x
100 mm) box with mud ring adapter (not provided) using
6-32 slotted Robertson™ screws.
Approval:
Underwriters Laboratories Listed: File No. E47434, Guide
No. XAPX.
CSA: File No. LR1322
Accesories (Not Included):
272804A Range Stop and Locking Screws Assembly:
Includes locking cover screws, Tinnerman clips,
wrench, and range stops—two plastic pins to insert
inside cover for field-selection of minimum and
maximum temperature settings.
272805H Replacement Cover Assembly: For T498B
Fahrenheit beige models (manufactured after
November, 1993—date coded after 9345).
Electrical Rating (Noninductive (resistive) rating):
22A noninductive at 120/208/240 Vac.
19A noninductive at 277 Vac.
ORDERING INFORMATION
When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the
TRADELINE® Catalog or price sheets for complete ordering number, or specify:
1. Order Number. 3. Accessories, if desired.
2. Switching. 4. Order additional system components and system accessories
separately.
If you have additional questions, need further information, or would like to comment on our products or services, please write or
phone:
1. Your local Home and Building Control Sales Office (check white pages of your phone directory).
2. Home and Building Control Customer Relations
Honeywell, 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386
In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9.
International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France,
Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.
95C-10686—3
2
T498A,B ELECTRIC HEAT THERMOSTATS
M6091A
ELECTRIC
HEATER
T1
L1
L1
(HOT)
L2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
USE SPECIAL SERVICE CO/ALR SOLDERLESS CONNECTORS
WHEN CONNECTING ALUMINUM CONDUCTORS OR A FIRE
HAZARD MAY RESULT.
BREAKS AND REMAKES BELOW -31°F(-35°C); NORMALLY
THERMALLY ACTIVATED. BREAKS ON A TEMPERATURE RISE;
MAKES ON A TEMPERATURE FALL.
USE A SEPARATE LIMIT CONTROL IN THE HEATING APPLIANCE.
1
2
3
4
3
2
4
T498A
1-1/4
(33)
1-1/32
(26)
15/16
(24)
5/8 (16)
2-3/32
(53)
1/2 (13)
M6089A
3-9/32
(83)
0
4
OFF
0
6
0
5
2-29/32 (72)
7
0
8
0
4-17/32
(116)
Fig. 1. Nominal dimensions in in. (mm).
RECYCLING NOTICE
If this control is replacing a control that contains
mercury in a sealed tube, do
control in the trash.
Contact your local waste management authority for
instructions regarding recycling and the proper
disposal of any control containing mercury in a
sealed tube.
not
place your old
Leave the cover on the thermostat while making
connections.
Push the leadwires into the outlet box and insert the
thermostat into the box for mounting by pushing against
the cover.
Remove the thermostat cover by grasping the top and
bottom edges and pulling outward.
Turn the dial so that the setpoint indicator is at the
12 o’clock position. This will prevent accidental damage
to the dial stop during mounting.
Using a screwdriver, secure the thermostat to the outlet
box by tightening the two mounting screws. Handle the
thermostat with care; excessive pressure can damage
the control knob or sensing element.
CAUTION
1. Disconnect power supply before making wiring
connections to prevent electrical shock or
equipment damage.
2. All wiring must comply with applicable codes and
ordinances.
3 Thermostats are designed to be used with a
separate limit control in the appliance.
Using wire connectors
approved for No. 12 wires,
make
line voltage wiring connections directly to the leadwires
installed on the thermostat.
CAUTION
If connecting with aluminum conductors, use approved
CO/ALR solderless wire connectors to avoid fire
hazard.
INSTALLATION
WARNING
HIGH VOLTAGE CONTROL.
ELECTRICAL SHOCK HAZARD.
This thermostat is a line voltage (120 to 277 volt)
control. Do not install this thermostat if you are not
completely familiar and competent with electrical
wiring. If improperly handled, there can be risk of 120
Location
Install a vertical outlet box that is used to mount the T498, four
to five feet (1.5m) above the floor on an inside wall where the
thermostat will be subjected to average room temperature.
Mount the thermostat away from concealed warm or cold water
pipes, warm air ducts, light switches and dimmers, refrigerators
or drafts from hallways, fireplaces, stairways or fans.
Mounting and Wiring
When replacing an old line voltage electric heating
thermostat, remove the old thermostat carefully to avoid
damaging the insulation on the wiring.
Check the old insulation for cracks, nicks, or fraying and apply
approved electrical tape where necessary to achieve adequate
insulation, or replace the wires using approved methods.
to 277 volt electric shock hazard that can cause
serious injury or death.
Fig. 2. Typical hookup for T498A Thermostat.
3
95C-10686—3
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